Stats showing overtaking during the refuelling era, yes the numbers were already dropping naturally before it came in but they drop sharply and stay firmly on the deck throughout the period.
You have to remember the big changes in technical regs during this period, stepped floors, narrow chassis, narrow treaded tyres, chopped diffusers, endless wing changes, engine freezes, rev limits, engine configuration changes, moveable aero, KERS, TC legal and illegal, engine capacity reduction and endless tyre wars but none of it had the slightest effect on overtaking. Refuelling is banned and BANG! we see passing again.
I can remember Hill Vs Schumacher in 94/95 and can remember the euphoria in the press when one of them passed the other on-track after about a year and a half of racing each other.......I'm glad to see the back of it personally.